How they work
A hot radiator warms the wall behind it. On an inside wall that heat stays in the house. On an outside wall, some of it passes through the brick or stone and is lost to the air outside.
A reflector panel sits between the radiator and the wall. Its shiny face reflects the heat coming off the back of the radiator into the room, and many have a thin layer of foam behind the foil that slows heat getting into the wall. A panel doesn't change the warm air that rises off the radiator and circulates around the room, which is how much of a radiator's heat reaches you. That is why the saving is real but small.
Which radiators to fit them behind
Only radiators on outside walls, and the less insulated the wall, the more the panel does. The Energy Saving Trust's rules of thumb for telling what kind of walls you have:
- Built before about 1920: the outside walls are likely to be solid brick or stone, with no insulation unless someone has added it inside or out. These are the walls where panels help most.
- Brick pattern: if some bricks are laid with their short ends facing out, the wall is probably solid. If every brick is laid lengthways, it is probably a cavity wall.
- Cavity walls: if the cavity has never been filled, a panel still helps a little. If it has cavity wall insulation, there is less heat for the panel to save.
Look at the room too. A bay window, a single-brick extension or a radiator under a window on a north-facing wall are usually the coldest places in the house, and the best spots for a panel.
What they save, compared with other fixes
The Energy Saving Trust's figures for Great Britain, which assume a typical home and current energy prices, put reflector panels well down the list of cheap fixes:
| What you do | Saving a year (Energy Saving Trust) |
|---|---|
| Reflector panels on uninsulated outside walls | About £18 |
| Draught-proofing windows, doors and floors | About £55 |
| Turning the thermostat down from 22°C to 21°C | About £120 |
So if you haven't stopped the draughts yet, do that first: see how to draught-proof a door and draught excluders and window film. Panels are a cheap extra once the bigger leaks are sealed. In Northern Ireland the Trust's figure for panels is about £20 a year.
Heating cost per hour See what an hour of heating costs with gas, oil, a heat pump or a plug-in heater.How to fit them
- Turn the radiator off at its valve, or turn the heating off, and let the radiator go cold.
- Measure the radiator's height and width. Cut the panel a little smaller all round, so it doesn't show past the edges once it's in.
- Hold the panel up to the radiator and mark where the wall brackets are. Cut slots so the panel slides down past them, and keep it clear of the valves and pipes.
- Slide the panel down behind the radiator, the way round the maker says (not all of them put the shiny side towards the radiator), and press it onto the wall with its tape. Clip-on sheets hang from the radiator brackets instead.
- Turn the radiator back on and check nothing is touching the valve or bleed screw.
If you're decorating and the radiator is already off the wall, that is the easiest time to fit one.
If you rent
Clip-on panels, which hang from the radiator rather than sticking to the wall, come out without marking anything. The Energy Saving Trust suggests asking your landlord before fitting any kind.
Our picks
Chosen by what each product is and how it fits, from the makers' own pages. We haven't tested them ourselves, and we don't repeat the makers' savings claims, because neither links to the test behind them.
If you rent, or don't want tape on the wall
Radflek Radiator Reflector, 3-sheet pack
- Type
- Radiator reflector
- Size
- 1200 x 600mm sheets
- Covers
- 3 to 6 radiators
- In the pack
- 3
Foil sheets that you cut to size with scissors and hang between the radiator's wall brackets on clips, so nothing sticks to the wall and they come out when you move. Each sheet covers up to two radiators, Radflek says.
For several radiators in a house you own
Heatkeeper Radiator Reflector Panels, 10-pack
- Type
- Radiator reflector
- Size
- 580 x 450 x 8mm panels
- Covers
- 4 to 5 average radiators
- In the pack
- 10
Ridged panels with a reflective face that stick to the wall behind the radiator with the tape supplied, two or three to a radiator. Heatkeeper says they work best with more than 20mm between the radiator and the wall, so measure that gap first.
Sources
- Energy Saving Trust: radiator reflector panels explained
- Energy Saving Trust: draught proofing
- Energy Saving Trust: solid wall insulation (how to tell solid from cavity walls)
Checked 24 October 2026.